There is now a change in economics. In the earliest times, one can guess advertising existed, in the form of hunters shouting "I have meat! Join me and not those others there!" in stone age eras. Or possibly "Best stone arrowheads here, get your's while they're sharp!"
Moving on to criers shouting "I have grain to exchange for things ! Best grain here!" in early farmer communities. Then land, property, inheritance, markets, money, than banks, and interest, loans, credit, state interest rates, inflation, unemployment, and all the rest of it.
So things change as time goes by.
What's changing now is that advertising has evolved. It was a service amplifying volumes of transactions for businesses, with advertising paid for by the revenue from those transactions (selling services, manufactured goods, and so on).
The evolution is one of scale: advertising still pushes up volumes of transactions, but advertising increasingly subsidises "free" sales of goods and services. The consumer has the illusion of being given free services in entertainment (newspapers, movies, sports, and so on) but pays for them indirectly via a little untraceable add-on to prices of things that are purchased under the influence of advertising.
Increasingly subtle advertising such as "suggested partner links" or "answer to questions by consumers looking for low cost trips, gardening tools, cheap books" ... the whole range of consumer products sold through advertising.
And the consumers are unaware of this. The common understanding is "Hey, we get free services!" , never pausing to think "How do they make any money ?".
The answer: Advertising works, which is why it increasingly permeates everything on the internet, adblockers or no.
That's a long answer to "was there ever an ad-free era".
The short answer: No, but advertising works, and advertising is taking on an ever greater role, moving from "a secondary sector just supporting delivery of goods and services", to "a primary sector supported by delivery of goods and services which often seem free".
I hope that's clear. It's complicated.